Boom suspension assembly

ABSTRACT

A mining shovel including a frame having an upwardly support member. A boom extends upwardly and forwardly from the frame from a connecting end toward a distal end along a boom longitudinal axis. At least one first suspension cable has one end attached to the boom proximal the boom distal end and an opposing end attached to the support member. The at least one first suspension cable defines an angle relative to the boom longitudinal axis, wherein in tension, the at least one first suspension cable resists a first side load imposed on the boom.

CROSS REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the priority benefit of U.S. ProvisionalPatent Application No. 60/238,065 filed on Oct. 5, 2000.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not Applicable.

BACKGROUND OF THE INVENTION

[0003] This invention relates to mining shovels, and more particularlyto a knee-action mining shovel with an boom supported by suspensioncables.

[0004] A conventional mining shovel generally includes a base supportedby ground engaging tracks. The base rotatably supports a frame on whichis mounted a housing for protecting mining shovel components, such aspower generation equipment, electrical equipment, a dipper hoist, andcontrols. The frame also supports a dipper assembly and boom. The dipperassembly includes a dipper which engages the ground.

[0005] The boom on a rope hoist mining shovel locates and supports boompoint sheaves, over which pass hoist ropes from the hoist machinery tothe dipper. When viewed from the side, the conventional boom structuregenerally lies on a line between the boom lower end connected to theframe, and the center of the boom point sheaves. Suspension cablessupport the angular position of the boom, and also aligned with theboom.

[0006] The boom must be designed to withstand side loads imposed uponthe load during mining operation. This requires a heavy boom formed fromexpensive material to withstand the side loads. A need exists for a boomsuspension system which can counteract side loads on the boom to providea mining shovel with a lighter weight boom which is less expensive toproduce.

SUMMARY OF INVENTION

[0007] The present invention provides a mining shovel including a framehaving an upwardly support member. A boom extends upwardly and forwardlyfrom the frame from a connecting end toward a distal end along a boomlongitudinal axis. At least one first suspension cable has one endattached to the boom, proximal the boom distal end and an opposing endattached to the support member. The at least one first suspension cabledefines an angle relative to the boom longitudinal axis, wherein intension, the at least one first suspension cable resists a first sideload imposed on the boom.

[0008] In another aspect of the invention, a boom suspension assemblyfor supporting a distal end of a boom includes a boom point box having alongitudinal axis. The longitudinal axis is parallel to a longitudinalaxis of the boom when the boom point box is fixed to the distal end ofthe boom. A first lug is fixed to the boom point box, and defines anangle greater than 0 degrees relative to the boom point box longitudinalaxis.

[0009] A general objective of the present invention is to provide sideload stability to the boom while reducing the boom weight. Thisobjective is accomplished by providing suspension cables whichcounteract side loads imposed on the boom during operation, thusallowing a reduction in the weight of the boom.

[0010] Another objective of the present invention is to reduce theweight of the boom point box. This objective is accomplished by aligningthe lugs connected to the angled suspension cables to reduce the sideloads on the lugs imposed by the angled suspension cables.

[0011] The foregoing and other objects and advantages of the inventionwill appear from the following description. In the description,reference is made to the accompanying drawings which form a part hereof,and in which there is shown by way of illustration a preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a perspective view of a mining shovel incorporating thepresent invention;

[0013]FIG. 2 is a perspective view of boom point box of the miningshovel of FIG. 1; and

[0014]FIG. 3 is a top view of the boom point box of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] A knee-action mining shovel 10, shown in FIGS. 1-3, includes abase 12 supported by ground engaging tracks 14. The base 12 rotatablysupports a frame 16 on which is mounted a housing 18 for protectingmining shovel components, such as power generation equipment, electricalequipment, a dipper hoist, and controls. The frame 16 also supports agantry 20, dipper assembly 22, and overhead boom 24. A dipper assembly22 is pivotally connected to the frame 16, and supports a dipper 26 forengaging the ground. A gantry 20 is fixed to the frame, and extendsabove the housing 12. An overhead boom 24 is pivotally connected to thegantry 20, and extends over the dipper assembly 22. The boom 24 supportshoist rope sheaves 25 which guide hoist ropes 28 attached to the dipper26.

[0016] The dipper assembly 22 includes a stiff leg 48 having a lower end50 pivotally connected to the frame 16 with pins 49 and an upper end 54pivotally connected to a dipper handle 52. The stiff leg 48 is pivotedabout the pins 49 by a crowd handle 53 to move the dipper handle in aforwardly or rearwardly direction.

[0017] The dipper handle 52 is a beam extending forwardly from the stiffleg 48 having a connecting end 70 pivotally connected to the stiff legupper end 56, and a dipper end 72. The dipper end 72 extends away fromthe frame 12 below the boom 24, and is connected to the dipper 26.Preferably, the dipper handle connecting end 70 is connected to thestiff leg upper end 56 by a universal joint to allow rotation about thedipper handle longitudinal axis.

[0018] The dipper 26 is pivotally connected to the dipper end 72 of thedipper handle 52, and engages the ground to extract minerals and thelike. The dipper 26 is a bucket, such as well known in the art formining shovels. The dipper 26 is guided in the forwardly and rearwardlydirections by the dipper handle 52, and is raised and lowered by thehoist ropes 28 suspended from the boom 24. Although pivotally connectingthe dipper 26 to the dipper handle 52 is preferred, the dipper 26 canalso be rigidly connected to the handle 52 without departing from thescope of the present invention.

[0019] The hydraulic crowd handle 53 pivots the stiff leg 48 about thepins 49 to move the dipper handle 52, and thus the dipper 26, in aforwardly and rearwardly direction. The crowd handle 53 has one end 55pivotally connected to the gantry 20 and an opposing end 57 pivotallyconnected to the stiff leg 48 proximal the stiff leg upper end 54.Actuation of the hydraulic crowd handle 53 pivots the stiff leg aboutthe pins 49. Although a hydraulic crowd handle is disclosed, other crowdhandles known in the art, such as a rack and pinion driven crowd handle,a rope driven crowd handle, and the like, can be used without departingfrom the scope of the present invention.

[0020] The boom 24 is an overhanging structure pivotally connected tothe gantry 20, and supports the dipper 26 above the ground. The boom 24has left and right legs 94, 96 pivotally connected to the gantry 20above the stiff leg lower end 50, and has a distal end 86 extendingforwardly over the dipper 26. An area 98 between the left and right legs94, 96 is open, which allows the stiff leg upper end 54 to slip betweenthe side legs 94, 96 when the stiff leg upper end 54 is pulled by thecrowd handle 53 to a maximum rearward position. A boom point box 42welded to the legs 94, 96 at the boom distal end 86 ties the legs 94, 96together.

[0021] The boom 24 extends upwardly from the gantry 20 along alongitudinal axis 87, and is held in its angular position by left andright upper suspension cables 88, 89. Each suspension cable 88, 89 hasone end 90 attached to a lug 36 fixed to the gantry 20 and an opposingend 92 (shown in FIGS. 2 and 3) attached to a lug 38 fixed to the boompoint box 42.

[0022] Importantly, the suspension cables 88, 89 are strung at an anglerelative to the boom longitudinal axis 87 to provide boom sidestability. In particular, two cables 88, 89 are strung at an angleoutwardly from each boom point box lug 38 toward one of the lugs 36fixed to the gantry 20. The gantry lugs 36 are spaced further apart thanthe boom point box lugs 38 to cause the cables 88, 89 to form an angle Bwith the boom longitudinal axis 87 which is greater than 0 degrees, suchas greater than 5 degrees. Preferably, angle B is greater than 7degrees.

[0023] In tension, the angled cables 88, 89 counteract side loadsimposed on the boom 24 during the operation of the shovel 10. Inparticular, the left suspension cables 88 counteract a side load imposedon the boom which is in a direction opposite to a side load counteractedby the right suspension cables 89. Advantageously, stringing thesuspension cables 88 at an angle to the boom 24 minimizes the potentialfor interference between the suspension cables 88 and the hoist ropes28. Preferably, the angled cables 88, 89, and thus the boom point lugs38, define lines 91, 93 which intersect within the perimeter of the boompoint box structure to avoid inducing a moment on the boom 24.

[0024] As shown in FIGS. 2 and 3, the welded-on boom point box 42incorporates both the boom point sheaves 25 and suspension cable lugs 38to reduce the bending moment on the connection between the boom pointbox 42 and legs 94, 96, and has a longitudinal axis substantiallyparallel to the boom longitudinal axis 87. The boom point box lugs 38are fixed, such as by welding to a top surface 44 of the boom point box42, at the angle B aligned with the cables 88 attached thereto toeliminate side loads on the lug 38, and thus reduce the structuralweight of the lug 38. The cables 88 are attached to the lugs usingmethods known in the art, such as yokes 46 fixed to a cable end andbolted to the lug 38.

[0025] The boom point sheaves 25 are rotatably mounted to the boom pointbox 42 above the dipper 26. Each sheave 25 supports one of the hoistropes 28 attached to the dipper 26. Each rope 28 is attached to a dipperside, passes over one of the boom point sheaves 25, and is wound up on adipper hoist. The hoist winds and unwinds the hoist rope 28 to raise andlower the dipper 26 using a single part hoist reeving method.Preferably, each hoist rope 28 is a wire rope sized using methods knownin the art, for the particular application, which depends upon thedipper duty and capacity rating.

[0026] While there has been shown and described what are at presentconsidered the preferred embodiments of the invention, it will beobvious to those skilled in the art that various changes andmodifications can be made therein without departing from the scope ofthe invention defined by the appended claims.

We claim:
 1. A mining shovel comprising: a frame having an upwardlysupport member; a boom extending upwardly and forwardly from said framefrom a connecting end toward a distal end along a boom longitudinalaxis; at least one first suspension cable having one end attached tosaid boom proximal said boom distal end and an opposing end attached tosaid support member, said at least one first suspension cable definingan angle relative to said boom longitudinal axis, wherein in tensionsaid at least one first suspension cable resists a first side loadimposed on said boom.
 2. The mining shovel as in claim 1, in which saidcable one end is spaced from said boom longitudinal axis a firstdistance and said cable opposing end is spaced from said boomlongitudinal axis a second distance, wherein said second distance isgreater than said first distance.
 3. The mining shovel as in claim 1, inwhich a boom point box is fixed to said boom distal end, and said cableone end is attached to a lug fixed to said boom point box.
 4. The miningshovel as in claim 3, in which said lug is aligned with the angle ofsaid cable.
 5. The mining shovel as in claim 1, in which at least onesecond suspension cable having one end attached to said boom proximalsaid boom distal end and an opposing end attached to said support memberon an opposite side of said longitudinal axis as said first suspensioncable, said at least one second suspension cable defining an anglerelative to said boom longitudinal axis, wherein in tension said atleast one second suspension cable resists a second side load imposed onsaid boom which is opposed to said first side load.
 6. The mining shovelas in claim 1, including at least one second suspension cable having oneend attached to said boom proximal said boom distal end and an opposingend attached to said support member, said at least one second suspensioncable defining an angle relative to said boom longitudinal axis, whereinlines defined by said first and second suspension cable intersect withinthe perimeter of said boom.
 7. A boom suspension assembly for supportinga distal end of a boom, said assembly comprising: a boom point boxhaving a longitudinal axis, said longitudinal axis being parallel to alongitudinal axis of the boom when said boom point box is fixed to thedistal end of the boom; and a first lug fixed to said boom point box,and defining an angle greater than 0 degrees relative to said boom pointbox longitudinal axis.
 8. The boom suspension assembly as in claim 7, inwhich at least one suspension cable is attached to said first lug andextending toward a first attachment point at an angle substantiallyaligned with said lug.
 9. The boom suspension assembly as in claim 7,including a second lug fixed to said boom point box, and defining anangle greater than 0 degrees relative to said boom point boxlongitudinal axis, wherein said second lug is not parallel to said firstlug.
 10. The boom suspension assembly as in claim 9, in which at leastone suspension cable is attached to said second lug and extending towardan attachment point at an angle substantially aligned with said secondlug.
 11. The boom suspension assembly as in claim 10, in which saidsuspension cable attached to said first lug defines a first line andsaid suspension cable attached to said second lug defines a second line,wherein said first and second lines intersect within the perimeter ofsaid boom point box.
 12. The boom suspension assembly as in claim 7, inwhich said first lug defines an angle greater than 5 degrees relative tosaid boom point box longitudinal axis.